The present disclosure generally relates to waveguide displays, and specifically to manufacturing optical grating elements with a variable etch heights and duty cycle.
Near-eye light field displays project images directly into a user's eye, encompassing both near-eye displays (NEDs) and electronic viewfinders. Conventional near-eye displays (NEDs) generally have a display element that generates image light that passes through one or more lenses before reaching the user's eyes. Additionally, NEDs in augmented reality systems are typically required to be compact and light weight, and to provide large exit pupil with a wide field-of-vision for ease of use. However, designing a conventional NED with materials of desired optical properties often results in a very low out-coupling efficiency of the image light received by the user's eyes due to mismatch in the size and shape of the grating element. While conventional lithography methods can produce optical grating elements with a variable duty cycle, such methods are incapable of modulating the height of the optical grating. Accordingly, there is a lack of a manufacturing system to fabricate optical grating elements with variable depths and duty cycles with a high throughput.